1. Field of the Invention
The present application relates to the field of electronics, and more particularly, to methods of forming electronic component packages and related structures.
2. Description of the Related Art
During fabrication of an electronic component package substrate, an upper circuit pattern is formed on or embedded within an upper surface of a dielectric layer. Similarly, a lower circuit pattern is formed on or embedded within a lower surface of the dielectric layer.
To electrically interconnect the upper circuit pattern with the lower circuit pattern through the dielectric layer, blind via apertures are formed through the upper circuit pattern and the dielectric layer to expose portions of the lower circuit pattern. The blind via apertures are filled with electrically conductive material to form blind vias electrically interconnecting the upper circuit pattern with the lower circuit pattern.
The blind via apertures are formed using laser-ablation, i.e., by using a laser to ablate through the upper circuit pattern and the dielectric layer to form the blind via apertures. Accordingly, the blind via apertures taper, i.e., are not perfectly cylindrical.
More particularly, the blind via apertures have a greater width at the upper circuit pattern than at the lower circuit pattern. The relatively large width of the blind via apertures at the upper circuit pattern places fundamental restrictions on the ability to minimize the feature size of the substrate.